The present invention relates to the manufacture of layered metal components and particularly to electrical terminals having solder cladding.
Electrical terminals must be connected to certain articles of manufacture to allow for the flow of electricity from one medium to a different medium. This is particularly true in instances where the conductive elements are embedded in a non-conductive material, such as glass or dielectric substrate. In, for instance, automotive glass panels having electrical wiring embedded therein for the purpose of defogging the window, electrical terminals must be attached to the glass panels to provide a point of connection for electrical current input and output.
Currently, such terminals are manufactured beginning with the step of obtaining a ribbon of copper, then cleaning, tin-plating, and reeling the ribbon. The ribbon is de-reeled, clad with a solder material on one side, and re-reeled. The ribbon of solder-clad copper is fed into a progressive stamping die that blanks out the flat terminal, then forms the terminal into its final shape. The terminals are connected to a carrier strip which is used to transfer the terminals along the multiple stations of the progressive stamping dye. The progressive stamping die cuts the individual terminal off of the carrier strip at its last station. The individual terminals are optionally cleaned and reclad with tin-plating or solder to cover the exposed copper where it was cut from the carrier strip.
The prior art method of forming electrical terminals has the disadvantage of producing a terminal with exposed copper. Such a terminal is subject to deterioration by oxidation. Alternatively, the terminals must be individually reclad to seal the copper. The task of cladding individual terminals adds expense to the process.
A method of producing layered metal components such as clad electrical terminals is described which obviates the need for cladding the terminals twice. The method of this invention includes the steps of providing a strip of base material, depositing a layer of material on the base material, such as cladding material, and cutting individual pieces from the strip in such a manner that the cladding material is wiped across the surface of the base material which would otherwise be exposed by the separation. The method optimally incorporates the use of a comparatively brittle base material, such as copper. The method also optimally includes the use of a soft layering material such as solder, or other lead-tin alloys. Finally, the method works best when a stepped punch is used to cut the individual terminals. The stepped punch includes a fine edge which trims the soft layering material, and a wider edge which both severs the base material and wipes the soft layering material over the newly exposed base material. A stepped die may be used rather than or in addition to a stepped punch.
It is therefore a principal object of the invention to provide a method of producing metal components which method includes the step of layering integrated components with layering material only once, but which produces individual components that are entirely covered with layering material.
It is another object of this invention to provide a method of forming electrical terminals which allows for the layering of integrated terminals, but which does not require re-layering of separated terminals.
Yet another object of this invention is to provide a method of producing layered metal components which are durable and inexpensive of manufacture.